Electronic timing and control means for relays



Apnl 12, 1949. w. A. BROWN 2,467,003

ELECTRONIC TIMING AND CONTROL MEANS FOR RELAYS Filed Dec. 2, 1947 .9 I 4a #39 I 6/ H16 Patented Apr. 12, 1949 ELECTRONIC TIMING AND CONTROL MEANS FOR RELAYS William A. Brown, Pensacola, Fla. Application December 2, 1947, Serial No. 789,302

9 Claims.

This invention relates to an electronically controlled delayed action relay for closing an electrical circuit after a predetermined period of delay and thereafter opening said circuit after it has been energized for a predetermined period, and is particularly adapted for use in controlling the circuit through the actuating solenoid of a motion picture projector change-over switch, though by no means limited to such use.

In the showing of motion pictures it is usual practice to employ a plurality of projecting machines, one of said machines being in operation to show one reel of film while the other is loaded with the succeeding reel of film and maintained in readiness to be brought into operation at the exact instant that the showing of the film on the first projector is completed. Both of said machines are connected to a standard solenoid actuated change-over switch which has heretofore required to be manually actuated by the projectionist at the exact proper-instant in order to result in a smooth change-over from one projector to the other.

In order to make such a change-over it has been necessary for the projectionist to watch the screen very carefully to detect visual change-over cues thereon, the first of these consisting of a warning or stand-by cue, which is followed after a predetermined interval by a change-over cue indicating the exact instant at which the changeover solenoid must be energized.

This has required that the projectionlst devote his entire time and attention to making the change-over with resulting eye-strain, fatigue and nevertheless occasional unsatisfactory change-overs.

With the foregoing in mind, the present invention has for its primary object to provide a control device or relay which, though capable of other applications, is particularly adapted for .controlling. the energizing of the solenoid circuit in such a change-over switch, requiring manual actuation only to initiate its operation at the time of the visual warning or stand-by cue.

A further object is to provide such a device which may be set to effect an interruption of the controlled solenoid or other circuit a prede termined interval after same has been energized.

A further object is to provide such a device employing adjustable relay control means for varying the period of delay prior. to energization of the controlled circuit and for also vary-- ing the period during which same remains energized.

A still further object is to provide signaling be considered as merely illustrative of the invention, and not as exclusive of other possible embodiments.

In the accompanying drawings, the figure represents a wiring diagram of apparatus embodying the invention.

Referring now in detail to the accompanying drawings, the embodiment of the invention shown therein by way of illustration comprises a suitable source of alternating current, such as a transformer having a primary coil I and secondary coils 2, 3 and 3' respectively.

A pair of thermionic rectifiers 5 and 5 respectively, preferably of the full wave type, serve as the timing and controlling elements of the invention, and each has its plate circuit and its filament circuit receiving current from said transformer.

By reference to the drawing, it will be seen that the plate circuit of rectifier 5 comprises the lines 6 and 1 respectively connecting the plates 8'8 thereof to opposite ends of the secondary coil 2; and in the plate circuit of rectifier 5 the plates 88 are similarly'respectively connected to opposite ends of the secondary coil 2, as bylines 6 and 1' respectively connected to said lines 6 and 1.

The filament circuit of rectifier 5 includes the lines 9 and I0 connecting the filament I l in series with the secondary coil 3 to receive alternating current therefrom, and any suitable preferably adjustable current regulating device or means such as the potentiometer l2 interposed in said circuit to control the filament voltage and consequently the time required to heat the filament l l to operating temperature. Preferably the arm or Wiper l3 of the potentiometer l2 will have associated therewith a gauge or scale M which is calibrated to indicate the time that will be required to heat the filament ll to'operating temperature at different settings of the wiper M, the Wiper serving as an index with relation to the calibrations on said scale.

' 3 has a filament circuit similar to including the lines 9' and ill connecting the filament in series with the secondary coil 3', a potentiometer l2 interposed in said circuit for the purpose aforementioned in connection with potentiometer l2, said potentiometer l2 preferably also having a scale It similar to scale I4 and for a similar purpose, though preferably the potentiometer I2 is adjustable to interpose a greater resistance in its respective filament circuit than is the potentiometer l2.

The rectifier 5 controls the closing of a normally open main or control relay, designated l5 Rectifier 5 that of rectifier 5, same in its entirety, which has its winding it normally connected to the filament circuit of rectifier 5, as by the line l1, and to the plate circuit of said rectifier through the center of secondary coil 2 by means of a line I; thereby establishing a direct current relay energizing circuit through the rectifier 5 and relay ii.

In order to eliminate alternating current from the relay winding l6, said energizing circuit may include a suitable filter consisting of a resistance I! in series with the relay winding l6, and a capacitor or condenser 20 connected inparallel with said winding and said resistance.

Control relay i5 includes an armature 2i and its cooperating contact 22 both included in a circuit 30 which is controlled by said relay l5. Current may be supplied to said circuit 30 from any suitable source. Normally the armature 2| will be retained in open position out of engagement with the contact 22 by means such as a spring 23, but will be moved into engagement with said contact when actuated by energization of the winding l6. Said winding i6 is energized as soon as the rectifier filament l l reaches operation temperature.

The rectifier 5' controls the opening of a normally closed cut-out relay l5 which has its armature 2| interposed at some suitable point to control the energizing circuit of control relay i5. Thus when winding l6 of the cut-out relay I5 is energized said armature 2i will move away from its contact 22' to de-energize the control relay l5, permitting the armature 2| thereof to be opened by spring23 to interrupt the controlled circuit 30.

Such a cut-out relay l5 may be included in the direct current energizing circuit of its respective rectifier 5' in a manner similar to that of the control relay l5. Thus the winding l6 of relay l5 may be connected to the plate and filament circuits of the rectifier 5 by means of the lines 18 and I1 respectively. The energizing circuit of said relay l5 may include a filter circuit consisting of the capacitor or condenser 20, resistance l9, and winding I6 for the same purpose and arranged in similar manner to the corresponding elements of the relay i5. Suitable means such as the spring 23' normally retain the armature 2| in engagement with its contact 22'.

The potentiometer l2 of the cut-out relay l5 will be set to cause actuation of the said relay IS a predetermined interval after the actuation of control relay ii.

In order that the fiow of current through the filament circuits of both rectifiers 5 and 5 may be commenced at exactly the same instant, I provide a suitable means for simultaneously controlling both of said filament circuits. Such means preferably consists of any usual time of manual switch S disposed in the supply line of the primary coil l of the transformer.

To the end that the operator may have some means of readily ascertaining that the filament circuit of the rectifier 5 is energized and that the timing and/or rectifying functions thereof are proceeding properly, a visual signal in the form of a suitably colored incandescent lamp 25 may be connected across said filament circuit,

'as shown. Such a light 25 will be illuminated continuously from the time the switch S is closed, providing the filament circuit is in order.

In order to further inform the operator as to the length of time that the cut-in relay I5 is closed, I provide additional signal means preferably consisting of a suitable colored signal light 26 which is connected across the filament circuit of the rectifier 5' by means of a line 21.

Disposed in the line 21 is a switch arm 28 for cooperation with a in said line 21. The switch arm 28 is coupled or ganged to the armature 2| of the relay l5 for simultaneous opening and closing therewith, so that, upon closing of the relay l5 and consequent energizing of the controlled device, the signal 26 will be actuated and will remain actuated until the cut-out relay l5 operates, at which time signal 25 will become immediately de-energized, thus indicating the opening of relay l5.

In practice the relay l5 may be of the double pole type, in which case the switch arm 28 may constitute one of the dual arms or armatures thereof.

In the operation of the invention the controlled circuit may have any desired electrical device or devices included therein. Where the invention is used for control of a projector change-over switch, as aforementioned, the actuating solenoid of such switch may be included in the controlled circuit 30.

With such arrangement, the projectionist will adjust the potentiometer l2 so that the delay between the time the filament is energized and the time it reaches operating temperature with resultant energization of the control relay 15, will be equal to the interval between the stand-by and change-over visual cues shown on the screen.

At the same time the potentiometer l2 will be adjusted to cause a somewhat longer delay in the energization of its associated relay IS, the diference in the periods of delay caused by said potentiometers l2 and i2 obviously equalling the period during which the controlled circuit remains energized.

With the device thus arranged, the projectionist need watch the screen only long enough to detect the first or stand-by visual cue, at which time he manually closes the switch S, simultaneously starting the motor of the incoming projector and initiating the operation of the device of the invention. At this time the indicator signal light 25 will fiash on and will stay on as long as its respective filament circuit is energized.

Thereafter, the heating of the filament H and the consequent operation of the rectifier 5 will close the relay IS, with resultant closing of the controlled circuit 30, thereby permitting energization of the solenoid or such other devices as may be included in said circuit.

Simultaneous with the closing of the relay IS, the signaling circuit 21 will be closed to energize the signal 26 and thereby indicate such closing.

After relay l5 has been closed for a predetermined interval, preferably of sufficient duration to insure complete operation of the solenoidactuated change-over switch, the subsequent coming into operation of the rectifier! and resultant contact 29 similarly disposedv opening of the relay 2 I will de-energize the relay 2|, which will then return to open position, breaking the controlled circuit 30 and avoiding danger of injury to the solenoid in said circuit 30.

I claim:

1. Electronic timing and control means comprising a transformer, a switch disposed in the primary circuit of said transformer and controlling the energization thereof, a pair of thermionic full Wave rectifiers each having a plate circuit and a filamentcircuit electrically connected to and receiving current from said transformer, current regulating means included in each said filament circuit, each said means being adjustable to delay the heating of its respective filament to operating temperature for various predetermined intervals following energization of said transformer, and a normally open control relay having an energizing circuit in series with one of said rectifiers to be energized by the rectified current therefrom, in combination with a normally closed cut-off relay having cooperating contacts disposed in the energizing circuit through said control relay, said cut-off relay having an energizing circuit connected to said other rectifier to be energized by the direct current therefrom and thus cause de-energization of said control relay after a given period of energization thereof.

2. Electronic timing means comprising a transformer, a pair of full wave thermionic rectifiers, each comprising a plate circuit and a filament circuit, both electrically connected to and receiving current from said transformer, adjustable current regulating means included in each said filament circuit to delay the actuation of its respective rectifier for a predetermined interval following the energization of said transformer, and a normally open cut-in relay in circuit with one of said rectifiers to be energized by the rectified current therefrom, in combination with a normally closed cut-off relay controlling the energizing circuit of said control relay, said cut off relay being connected to said other rectifier tube to be energized by the rectified current therefrom, and thus cause de-energization of said control relay. v

3. Electronic timing means comprising a transformer, a pair of full wave thermionic rectifiers, each comprising a plate circuit and a filament circuit, both of said circuits being electrically connected to and receiving current from said transformer, resistances included in said respective filament circuits to delay for predetermined intervals the heating of their respective filaments to operating. temperature and the resultant actuation of their respective rectifiers, said resistances being of such relative values that the first of said rectifiers commences actuation a definite interval before the second thereof, and a normally open cutin relay having an energizing circuit in series with said first rectifier to be energized by the rectified current therefrom, in combination with a normally closed cut-out relay having an energizing circuit in series with said other rectifier to be energized by the rectified current therefrom, said cut-out relay having cooperating contacts in the energizing circuit to said cut-in relay to de-energize same a predetermined time after its energization has commenced.

4. Electronic timing and control means comprising a source of alternating current, and a control switch in circuit therewith, a pair of thermionic full wave rectifiers, each comprising a plate circuit and a filament circuit, both of said circuits being electrically connected to and receiving current from said source, an adjustable resistance included in each said filament circuit to delay the heating of its filament and the consequent actuation of its respective rectifier for a predetermined interval following the closing of said control switch, and a normally open control relay having an energizing circuit connected to one of said rectifiers to be energized by the rectified current therefrom, in combination with a normally closed cut-out relay having an energizing circuit connected to said other rectifier to be energized by the rectified current therefrom, said cut-out relay having circuit interrupting means disposed in and controlling the energizing circuit of said cut-in relay.

5. Electronic timing and control means comprising a source of alternating current, a pair of thermionic rectifiers, each having a plate circuit and a filament circuit electrically connected to and receiving current from said source, a common control switch in circuit with both of said filament circuits, means included in each of said filament circuits to delay the heating of the filament thereof for a predetermined interval following the closing of said switch, and a cut-in relay having an energizing circuit connected to one of said rectifiers to be energized by the rectified current therefrom, in combination with a cut-out relay comprising an energizing circuit connected to the other of said rectifiers to be energized by the rectified current therefrom, and circuit interrupting means energized by said energizing circuit of the cut-out relay, said means comprising actuating means and contacts controlled thereby, said contacts being disposed in the energizing circuit of the cut-in relay.

6. Electronic timing and control means comprising a source of alternating current, a pair of thermionic rectifiers, each having a plate circuit and a filament circuit electrically connected to and receiving current from said source, a common control switch in circuit with both of said filament circuits, means included in the filament circuit of the first of-said rectifiers for retarding the actuation thereof relative to the second of said rectifiers, and a control relay in circuit with said second rectifier to be energized by the rectified current therefrom, in combination with a cutout relay in circuit with said first rectifier to be energized by the rectified current therefrom, said cut-out relay being disposed to control the energizing circuit of said control relay.

7. Electronic timing and control means comprising a source of alternating current, a pair of thermionic rectifiers, each having a plate circuit and a filament circuit electrically connected to and receiving current from said source, a common control switch in circuit with both of said filament circuits, means included in the filament circuit of the first of said rectifiers for retarding the actuation thereof relative to the second of said rectifiers, and a control relay in circuit with said second rectifier to be energized by the rectified current therefrom, in combination with a cut-out relay in circuit with said first rectifier to be energized by the rectified current therefrom, said cut-out relay being disposed to control the energizing circuit of said control relay, a signaling circuit including a signaling device connected across the filament circuit of said first rectifier, and a switch disposed in said circuit for actuation by said control relay to close said circuit and energize said signaling device during the period when said control relay is energized.

8. Electronic timing and control means comprising a source of alternating current, a pair of thermionic rectifiers, eachhaving a plate circuit and a filament circuit electrically connected to and receiving current from said source, a common control switch in circuit with both of said filament circuits, means included in the filament circuit of the first of said rectifiers for retarding the actuation thereof relative to the second of said rectifiers, signaling means connected across the filament circuit of said second rectifier to indicate when same is energized, and a control relay in circuit with said second rectifier to be energized by the rectified current therefrom, in combination with a cut-out relay in circuit with ergizing circuit connected to said second rectisaid first rectifier to be energized by the rectified current therefrom, said cut-out relay being disposed to control the energizing circuit of said control relay, a signaling circuit including a signaling device connected across the filament circuit of said first rectifier, and a switch disposed in said circuit for actuation by said control relay to close said circuit and energize said signaling device during the period when said control relay is energized.

9. Electronic timing and control means comprising a source of alternating current, a pair of thermionic rectifiers, each having a plate circuit fier for energization by the rectified current therefrom, in combination with means actuated by the rectified current irom said first rectifier for interrupting the energizing circuit through said control relay.

' WILLIAM A. BROWN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,720,662 Burke July 16, 1929 2,047,127 Huber July 7, 1936 2,339,750 Bartholy Jan. 25, 1944 2,360,721 Rose Oct. 17, 1944 

